Viewing archive of Monday, 18 April 2005
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2005 Apr 18 2210 UTC# Prepared jointly by the U.S. Dept. of Commerce, NOAA, #Space Environment Center and the U.S. Air Force. #
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 108 Issued at 2200Z on 18 Apr 2005IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity was low. Region 755 (S11E67) produced a
C4.6 flare at 17/2107 UTC. An associated CME was first observed on
LASCO C2 imagery at 17/2126 UTC off the east limb. The CME is not
expected to be geoeffective. No new regions were numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be very
low to low.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was quiet to unsettled with an isolated active
period at mid latitudes. The greater than 2 MeV electron flux at
geosynchronous orbit reached high levels today.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be quiet to unsettled with possible isolated active
conditions due to the effects of a coronal hole high speed stream
moving into geoeffective position.
III. Event Probabilities 19 Apr to 21 Apr
| Class M | 10% | 10% | 10% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Apr 081 Predicted 19 Apr-21 Apr 080/080/080 90 Day Mean 18 Apr 092
V. Geomagnetic A Indices
Observed Afr/Ap 17 Apr 004/005 Estimated Afr/Ap 18 Apr 005/009 Predicted Afr/Ap 19 Apr-21 Apr 010/012-008/012-010/012
VI. Geomagnetic Activity Probabilities 19 Apr to 21 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 20% | 25% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 25% | 25% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 05% | 05% | 05% |
All times in UTC
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